1. Field of the Invention
The present invention relates generally to computer-assisted design of models and, more specifically, to a system and method of automatically generating a family of mesh models for use in Computer-Aided Engineering (CAE) analysis.
2. Description of the Related Art
The design process of a product, such as an automobile, has advanced to a state in which computer-assisted design techniques are frequently incorporated in the development of the product, or redesign of an existing product. At the same time, enhanced visualization software tools have been developed that allow for interactive display and manipulation of large-scale geometric models of the product, including models developed using Computer-Aided Design (CAD).
Computer-assisted design techniques are typically utilized in the design of a vehicle model. The combined use of CAD and visualization techniques are especially beneficial in designing, packaging and assembling the various systems incorporated within the vehicle, to maximize the design and functional capabilities of these vehicles. Advantageously, potential vehicle system designs can be considered in a timely and cost-effective manner by analyzing a digital representation of a proposed design, versus preparing a physical prototype of the vehicle.
One aspect of the design process is to construct a geometric model of the proposed design using a technique known as Computer-Aided Design (CAD). Another aspect of the design process is the use of mathematical tools, collectively referred to as Computer-Aided Engineering (CAE), to constrain and guide the designer in evaluating the design and to optimize the performance of the product. The use of a CAE simulation allows for verification of a design intent, and a prediction of a mechanical behavior of the design, including its systems, subsystems and components, and suggestions for improvements. CAE simulations are advantageous in particular types of vehicle analysis, such as vehicle aerodynamics analysis, safety analysis and structural analysis. Examples of CAE techniques include Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD). Recent enhancements to the computing and software power of modern computers have resulted in a significant reduction in the amount of computer (CPU) time required to perform an analysis, such as an FEA run. Therefore, CAE tools can be utilized much earlier in the product development process and applied to a wider range of product development activities.
An emerging trend in the product development process as a result of enhanced CAE computational capabilities is Design of Experiments (DOE) utilizing CAE results rather than results collected from testing physical prototypes. DOE is an engineering design practice that enables a designer to conduct a series of tests corresponding to variations in a set of predetermined design parameters. One benefit of a CAE-based DOE is that a test that, in the past would require a physical experiment on a physical prototype, can now be performed using a CAE simulation and a geometric (digital) model. As a result, the DOE can be conducted in an early phase of the product development process, and proposed modifications to the design can be expeditiously analyzed. For example, an airflow DOE provides aerodynamic information regarding the exterior shape of the vehicle for use in the design of the exterior shape of a vehicle. CFD is utilized to calculate aerodynamic properties, ranging from drag and lift coefficients to wind-noise characteristics, in response to a set of vehicle exterior shape parameters. Since the CFD simulation uses a geometric model of the vehicle, the airflow DOE can be performed early in the design process, before a physical prototype is built.
Currently, the CAD model of a product is converted into a mesh model suitable for CAE analysis, such as a finite element mesh model. The Computer-Aided Engineering (CAE) simulation is performed by the user using a predetermined set of parameters, and the results of the simulation are available for additional study and evaluation. If the user wants to change a design parameter based on the generated response, the CAD model is modified in light of the changed design parameter, and the updated CAD model is converted into a model format suitable for CAE analysis.
A significant disadvantage of the prior art is that the step of modifying a CAD model is costly and time-consuming to implement, since it must be performed each time a change is made to the set of DOE parameters. A CAD system requires a significant amount of overhead, including user-time, training and experience. The cost and time associated with having to use a CAD system to update the mesh model detracts from the advantages associated with using a CAE simulation, such as in a DOE analysis.
A system and methodology of performing a CAE simulation using direct mesh manipulation of a mesh model is illustrated is also described in commonly assigned U.S. patent Ser. No. 09/681,732, which is hereby incorporated by reference. Advantageously, the use of direct mesh modeling expands and integrates a mathematical surface modeling technique referred to in the art as Direct Surface Manipulation, or DSM. With DSM, an entire surface feature is placed on an existing parametric surface as a single geometric entity. After the feature is created, a user can control its location, shape and continuity independently by adjusting corresponding parameters.
This system and methodology works well in directly modifying a feature of a mesh model using a technique such as Direct Surface Manipulation or Free-Form Deformation. However, it is desirable that additional productivity be gained with the ability to save a deformation applied to a model and apply it later or even to a different model without the need to recreating it from scratch. This notion of feature library or catalogue is, however, not included in the prior art.
Thus, there is a need in the art for a system and method for a user to interactively utilize a mesh feature catalogue to automatically and properly apply features to a base model and then generate a family of output meshes for further analysis such as for a Design of Experiment study.